[all-commits] [llvm/llvm-project] c6ff3c: [InstSimplify] Constant fold icmp of gep

[Nikita Popov via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: c6ff3c9bad88d2cd027a8d0149baf1b541b84653
      https://github.com/llvm/llvm-project/commit/c6ff3c9bad88d2cd027a8d0149baf1b541b84653
  Author: Nikita Popov <nikita.ppv at gmail.com>
  Date:   2020-03-04 (Wed, 04 Mar 2020)

  Changed paths:
    M llvm/lib/Analysis/InstructionSimplify.cpp
    M llvm/test/Transforms/InstSimplify/compare.ll

  Log Message:
  -----------
  [InstSimplify] Constant fold icmp of gep

InstSimplify can fold icmps of gep where the base pointers are the
same and the offsets are constant. It does so by constructing a
constant expression icmp and assumes that it gets folded -- but
this doesn't actually happen, because GEP expressions can usually
only be folded by the target-dependent constant folding layer.
As such, we need to explicitly invoke it here.

Differential Revision: https://reviews.llvm.org/D75407